Pharmaceutical manufacturing is based on control over the composition and bioactivity for each manufactured batch. This standardization and control provides reproducible material in the predictable and consistent treatment of patients. Herbal medicines, produced from botanical materials, have presented a unique problem for manufacturers desiring the control, reproducibility, and standardization that are required of pharmaceuticals. This problem is primarily due to the plurality of components contained in an herbal medicine and the large variation in composition and potency due to the growing, harvesting and processing conditions of raw materials.
Plants have been, and continue to be, the source of a wide variety of medicinal compounds. For centuries, various forms of botanically derived materials have been used to treat countless different ailments. The botanical materials have typically been in the form of powders made from one or more plants or plant parts or extracts derived from whole plants or selected plant parts. These powders and extracts are, for the most part, complex mixtures of both biologically active and biologically inactive compounds.
Although plant powders and extracts have been used widely for medicinal purposes, there are a number of problems associated with the use of such medicaments. For example, the complex chemical nature of the botanical materials makes it difficult to use the botanical materials in any type of controlled and predictable manner. The potential variations in the chemical composition of different batches of material obtained from different plant harvests makes such materials unsuitable for use in clinical situations.
On a positive note, the complex groupings of bioactive components typically found in botanical materials presents the potential for synergistic or additive bioactivity profiles. However, these potential increases in medicinal effectiveness are not predictable due to the unknown nature of these complex materials.
The above problems associated with the inherent chemical complexity of botanical medicaments has resulted in a great deal of effort being directed to the separation and isolation of the biologically active components from numerous medicinally important botanical materials. This area of endeavor has expanded rapidly in conjunction with the many improvements in chemical separation and analysis technology. Once isolated and purified, the various active components are used in clinical settings to establish the medicinal effectiveness of a specific component. Separation and purification of individual components from botanical materials is the cornerstone of this type of drug development procedure. Once purified, the suspected active component is typically mixed with a pharmaceutically acceptable carrier and subjected to further studies in laboratory animals and eventual clinical trials in humans. Upon proof of clinical efficacy, these types of drugs are considered to be pharmaceutical grade because they contain a single, or at most a small number of, well-characterized compounds which are present in known quantities.
Pharmaceutical grade drugs are advantageous in that they allow careful tracking of the effects of individual compounds in treatment protocols. Further, the dosage of the drug can be carefully controlled to provide relatively predictable medicinal action. A disadvantage of the relative purity of such pharmaceutical grade drugs is that the potential for complex and synergistic biological activity provided by naturally occurring plant materials is reduced because of the isolation of the drug from its natural environment. The study of isolated products may also represent artifacts produced by breakdown of sensitive biological/botanical complexes. The potential benefit provided by such synergistic activity is believed by many industry experts to be outweighed by the clinical risks associated with the use of complex plant materials which are not well characterized or controlled in a clinical setting.
Although isolation and purification of single compounds from plant materials has been a popular form of drug research and development, there has also been interest in studying complex botanical extracts to characterize their medicinal qualities. Many complex plant materials and extracts exist which have potent, but relatively unpredictable, medicinal properties. These materials are, for the most part, useless in a clinical setting because of the inherent risks involved with treating patients with poorly characterized materials which have no established batch consistency and which may differ widely in composition. Accordingly, there is a need to provide methods for standardizing such complex botanical materials so that they may be used more effectively in clinical research and patient treatments.